2 Remote sensing and geographyGEOG3610 Remote Sensing and Image InterpretationRemote sensing and geographyWhat is remote sensing?Development of remote sensingObservations of the Earth’s surfaceCommunication and data collection systemsImage ProcessingUse of remote sensing in geographyRemote Sensing and Geography

3 GEOG3610 Remote Sensing and Image InterpretationWhat is remote sensing?Remote sensing is the acquisition of information about an object without physical contact.It includes photographic and digital remote sensors.Aircraft and satellites are major platforms for the sensors.Remote Sensing and Geography

4 GEOG3610 Remote Sensing and Image InterpretationWhat is remote sensing?Observation of a target by a device separated from it by some distanceWhat is measured?“lights” or “colour” - to discuss laterHow are the photographs and images createdairborne and satellite dataHow can I use the imagesidentifying things, interpretation, see the changeRemote Sensing and Geography

6 Development of remote sensingGEOG3610 Remote Sensing and Image InterpretationDevelopment of remote sensingThe term “remote sensing” was coined in the early 1960’s by geographers in the Office of Naval Research of USA to apply to the information derived from photographic and non-photographic instruments.Remote Sensing and Geography

8 1860 picture of Boston HarbourGEOG3610 Remote Sensing and Image Interpretation1860 picture of Boston HarbourThis 1860 picture of Boston Harbour is thought to be the first aerial photograph taken in the US. The exposure was made from a balloon at an altitude of about 365m above the groundRemote Sensing and Geography

9 Old air-borne platformsGEOG3610 Remote Sensing and Image InterpretationOld air-borne platformsAbove: Stalwart pigeon photographers prepare to work. The tiny pigeon cameras were designed in 1903 and weighed about 70g. Right: Peering down a camera viewfinder from the open cockpit of a Curtiss Jenny, a flier practices the early techniques of aerial photography.(Courtesy Strain and Engle, 1992)Remote Sensing and Geography

19 1999: EOS-AM 1 (Terra Spacecraft)GEOG3610 Remote Sensing and Image Interpretation1999: EOS-AM 1 (Terra Spacecraft)Terra is the first of the NASA’s Earth Observing System satellite series. It was launched in December 1999 and activated for science operation on 24 February 2000.Courtesy terra.nasa.govRemote Sensing and Geography

21 GEOG3610 Remote Sensing and Image Interpretation2001: QuickBirdCommercial remote sensing system developed and operated by DigitalGlobeLaunched on 18 October 2001Ground resolution:Panchromatic: 61cmMultispectral: 2.44mRemote Sensing and Geography

22 Comparison of the two major periods in the history of remote sensingGEOG3610 Remote Sensing and Image InterpretationComparison of the two major periods in the history of remote sensingRemote Sensing and Geography

23 How does remote sensing work?GEOG3610 Remote Sensing and Image InterpretationHow does remote sensing work?recording and measuring electromagnetic radiation from the target.This recording and measurement can be taken by airborne or satellite sensors.Remotely sensed images are rectified and enhanced to show information better.We interpret the images to get information on given locations for mapping, management, etc.Remote Sensing and Geography

24 Observation of the earth’s surfaceGEOG3610 Remote Sensing and Image InterpretationObservation of the earth’s surfaceFor geographers, we use remote sensing to observe the Earth’s surface.Air photographs offer detailed view of the Earth’s surface but limited by many factors.Satellite photographs and images provide less detailed but more variety of information with a large and regular coverage.Remote Sensing and Geography

25 Causes of differences in scale of aircraft and satellite observationsGEOG3610 Remote Sensing and Image InterpretationCauses of differences in scale of aircraft and satellite observationsSatelliteAircraftHundreds of kilometresThousands of metresRemote Sensing and Geography

26 Passive and active remote sensingGEOG3610 Remote Sensing and Image InterpretationPassive and active remote sensingPassive remote sensing: the sensor detects the reflectance of sunlight from the surfacee.g. photographs, multispectral scannersActive remote sensing: the sensor detects the reflectance of the signal sent by the remote sensing systeme.g. RADARRemote Sensing and Geography

29 Communication and data collection systemsGEOG3610 Remote Sensing and Image InterpretationCommunication and data collection systemsRemotely sensed data has to be transmitted back to the Earth.A network of satellite receiving stations have been established over the world to receive data.Some satellite data can be directly received by small instruments.Data are available through variable commercial channels (e.g. EOSAT).Remote Sensing and Geography

31 GEOG3610 Remote Sensing and Image InterpretationImage processingDigital images are the major types of today’s remotely sensed data.They are fundamentally numbers.To make sense of them, a technology called image processing is employed to distort, enhance and extract information from the images.Image processing and interpretation are the focus for this subject.Remote Sensing and Geography

32 Use of remote sensing in geographyGEOG3610 Remote Sensing and Image InterpretationUse of remote sensing in geographyRemote sensing can bring us accurate, cheap and frequently updated information about the Earth’s surface.GIS is the optimum tool to handle and integrate large amount of spatially referenced data including remotely sensed data.Many things and phenomena in the real world are spatially referenced.Remote Sensing and Geography

33 Some examples of applicationsGEOG3610 Remote Sensing and Image InterpretationSome examples of applicationsAgricultureForestryEnvironmentUrban and regional planningMineral resourcesand many more...Remote Sensing and Geography